Diagnosis A small gonochoristic species that inhabits mud tubes within a sponge. Prostomium is rounded, caruncle extends to the posterior of chaetiger 2. Eyes are present (one pair) or absent, nuchal tentacle is absent. Branchiae are absent. Epithelial bacillary glands are present on chaetigers 2-11, seldom to 12. Glandular pouches are present on chaetigers 6-11. Chaetiger 5 has a ventral and a dorsal superior fascicle of capillary chaetae, and two types of major notopodial spines: (1) anterior spines expanded distally with one main tooth and a sub-terminal collar bearing numerous small teeth along margin; and (2) slightly falcate posterior spines. The pygidium is reduced, smaller in width than the terminal chaetiger, with 4-6 small lobes, ventral pair largest.[details]

Distribution New Zealand, known only from Northern North Island [details]

Etymology The specific epithet vestalis refers to the Roman deity Vesta, goddess of home and hearth, in reference to the species' reproductive forms (adelphophagy and architomic fragmentation), which both result in progenuy likely to settle near the parental tube (Paterson & Gibson, 2003: 739). [details]

Reproduction The species exhibits sexual and asexual reproduction. Low numbers of sexually mature specimens and egg strings were collected from November to January (sampling was not conducted during other months). All egg strings contained few embryos and large numbers of nurse eggs (adelphophagy) with offspring hatching as 15—17-chaetiger late-stage larvae. Architomic fragmentation was the dominant form of reproduction and occurred concurrently with sexual reproduction within the population. For more details see Gibson & Paterson (2003). [details]